what is variable change

What is Variable Change?

Learn about Variable change with Kevin Spacey!
21 2008

Case breakdown: Movie 21

The movie scene shows the professor playing the Monty Hall game with his students. Monty Hall was a Canadian game show where the host would offer the contestants 3 doors. One of the doors would have a luxury car behind it while the other two had goats. The contestant would obviously want to open the door with a car behind it instead of a goat. Ben bases his answer of door choices on variable change.

This blog, Learning Perspectives will explore the meaning of Variable change.

What is Variable Change?

Variable Change in Statistics helps in solving this Monty Hall problem. This problem calls for you to not consider your emotions and only use logic like all problems in Maths and Statistics.

So what emotions am I talking about? I’m talking about emotions of greed, impatience, and selfishness. If you’re able to put a lid on these emotions and not act on them, this problem is easy to solve with logic. As mentioned, the host will ask the contestant to pick a door out of 3 doors, once you pick a door, say door#2, the Host will open another door say door#1 to show there’s a goat behind the door.

Now he will give the contestant an option to either stay with their earlier choice i.e. door no. 2 or switch to door no. 3. Now as a contestant, you might think there is a 50% chance that you might win or lose. But that isn’t the case, let’s understand how.

what is variable change?

When you are offered 3 doors, you have a 1/3 chance with a door you picked (i.e. door 2), i.e. 33% chance to win the car.

Now that means the other 2 doors, i.e. door 1 and door 3 have a 2/3rd or 66.67% chance they have the car in them. Now, Monty Hall would open door 1 to show you that there’s a goat behind it. The host will now ask you to either switch or stay with the door selected earlier. (i.e. door 2)

Well, according to variable change one should always switch, since both door 1 and door, 3 had a 2/3rd chance of winning, and once door 1 was revealed to have a goat behind it. Door 3 automatically becomes more preferable as door 1 has a 33.33% chance of winning while door 3 now has a 66.67% chance of winning.

A contestant is faced with a 50% chance of winning is actually an illusion. He/ She is faced with a 66.67% chance of winning. Hence, as a contestant, one should always switch as it increases the chances of winning.

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